perf tools: Add flex support for parse_events_error

perf tools: Add flex support for parse_events_error

Allowing flex parser to report back event parsing error, like:

  $ perf record -e cycles,cache-mises ls
  event syntax error: '..es,cache-mises'
                                 \___ parser error
  ...

Signed-off-by: Jiri Olsa <[email protected]>
Cc: David Ahern <[email protected]>
Cc: Namhyung Kim <[email protected]>
Cc: Paul Mackerras <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Arnaldo Carvalho de Melo <[email protected]>